Examination of a blood vessel based on nuclear resonant absorption

Patent metadata

Field	Value
Publication number	US-11529111-B2
Application number	US-201917265561-A
Country	US
Kind code	B2
Filing date	Aug 6, 2019
Priority date	Aug 7, 2018
Publication date	Dec 20, 2022
Grant date	Dec 20, 2022

Abstract

The invention relates to a system and a method for determining a characteristic of a blood vessel portion, which comprises blood including a contrast agent exhibiting resonant absorption of x-ray photons at a specific energy. The system comprises a tunable monochromatic x-ray source (21) emitting x-ray radiation, an x-ray detector device (22) for detecting the x-ray radiation after it has travelled through the blood vessel portion. A control unit (26) varies a tuning of the x-ray source (21) to vary the energy of the x-ray radiation emitted by the x-ray source (21), and an evaluation unit (27) determines a tuning of the x-ray source (21) at which nuclear resonant absorption of the x-ray radiation incident onto the blood vessel portion occurs and estimates the characteristic on the basis of the determined tuning. The characteristic may particularly be the blood velocity in the blood vessel portion.

First claim

The invention claimed is:

1. A system for determining at least one characteristic of a portion of a blood vessel, the system comprising:
a tunable monochromatic x-ray source configured to emit x-ray radiation;
an x-ray detector configured to detect the x-ray radiation after travelling through the portion of the blood vessel and provide a detection signal indicative of an intensity of the detected x-ray radiation, the portion of the blood vessel comprising blood including a contrast agent exhibiting nuclear resonant absorption of x-ray photons;
a controller configured to vary a tuning of the x-ray source thereby varying energy of the x-ray radiation emitted by the x-ray source; and
an evaluation unit configured to determine, based on the detection signal, the tuning of the x-ray source at which nuclear resonant absorption of the x-ray radiation incident onto the portion of the blood vessel occurs and estimate the at least one characteristic based on the determined tuning.

2. The system as defined in claim 1 , wherein the contrast agent comprises iodine-127.

3. The system as defined in claim 1 , wherein the evaluation unit is configured to determine the tuning of the x-ray source at which nuclear resonant absorption of the x-ray radiation incident onto the portion of the blood vessel occurs by determining, based on the detection signal, the tuning of the x-ray source at which a maximum attenuation of the x-ray radiation travelling through the portion of the blood vessel occurs.

4. The system as defined in claim 1 , wherein the at least one characteristic of the portion of the blood vessel comprises a velocity of the blood flowing in the portion of the blood vessel.

5. The system as defined in claim 4 , wherein the evaluation unit is further configured to determine the velocity of the blood in the portion of the blood vessel based on an orientation of the portion of the blood vessel.

6. The system as defined in claim 5 , wherein the orientation of the blood vessel is determined based on a three-dimensional image of the portion of the blood vessel comprising the blood including the contrast agent.

7. The system as defined in claim 4 , wherein the evaluation unit is further configured to determine the velocity of the blood based on an angle between a longitudinal direction of the portion of the blood vessel and a travelling direction of x-ray photons included in the x-ray radiation.

8. The system as defined in claim 4 , wherein x-ray photons included in the x-ray radiation travel through the portion of the blood vessel with an angle other than 90° between a travelling direction of the x-ray photons and a longitudinal direction of the portion of the blood vessel.

9. The system as defined in claim 6 , wherein the x-ray source and the x-ray detector are moveable such that the x-ray radiation emitted by the x-ray source travels through the portion of the blood vessel under different angles and that the x-ray detector registers projections values of the blood vessel corresponding to the different angles, and wherein the three-dimensional image is generated from the projection values in accordance with a computed tomography reconstruction.

10. The system as defined in claim 3 , further comprising a gating unit adapted to provide a gating signal for controlling the x-ray source to emit x-ray radiation only during times corresponding to a predetermined portion of a cardiac cycle of the patient.

11. The system as defined in claim 1 , wherein the characteristic of the portion of the blood vessel comprises an anatomy thereof and/or a spatial distribution of calcium included in the portion of the blood vessel.

12. The system as defined in claim 11 , further configured to produce an x-ray image based on the detection signal acquired at the tuning of the x-ray source at which the maximum attenuation of the x-ray radiation travelling through the blood vessel occurs.

13. The system as defined in claim 12 , wherein the evaluation unit is configured to determine a position of calcium in the portion of the blood vessel and/or a degree of calcification of the portion of the blood vessel based on the produced x-ray image.

14. A computer-implemented method for determining at least one characteristic of a portion of a blood vessel, the method comprising:
controlling a tunable monochromatic x-ray source to emit x-ray radiation;
detecting the x-ray radiation after travelling through the portion of the blood vessel, wherein the portion of the blood vessel comprises blood including a contrast agent exhibiting nuclear resonant absorption;
varying a tuning of the x-ray source, thereby varying energy of the x-ray radiation emitted by the x-ray source;
determining, based on the detection signal, the tuning of the x-ray source at which nuclear resonant absorption of the x-ray radiation incident onto the portion of the blood vessel occurs; and
estimating the at least one characteristic based on the determined tuning.

15. A non-transitory computer-readable medium having executable instructions stored thereon which, when executed by at least one processor, cause the at least one processor to perform a computer-implemented method for determining at least one characteristic of a portion of a blood vessel, the method comprising:
controlling a tunable monochromatic x-ray source to emit x-ray radiation;
detecting the x-ray radiation after travelling through the portion of the blood vessel, wherein the portion of the blood vessel comprises blood including a contrast agent exhibiting nuclear resonant absorption;
varying a tuning of the x-ray source, thereby varying energy of the x-ray radiation emitted by the x-ray source;
determining, based on the detection signal, the tuning of the x-ray source at which nuclear resonant absorption of the x-ray radiation incident onto the portion of the blood vessel occurs; and
estimating the at least one characteristic based on the determined tuning.

Assignees

• Koninklijke Philips Nv

Inventors

• Daerr Heiner

Classifications

• A61B6/466

  adapted to display 3D data · CPC title

• A61K49/0004

  Screening or testing of compounds for diagnosis of disorders, assessment of conditions, e.g. renal clearance, gastric emptying, testing for diabetes, allergy, rheuma, pancreas functions · CPC title

• A61B6/405

  Source units specially adapted to modify characteristics of the beam during the data acquisition process (A61B6/4021, A61B6/4035 take precedence) · CPC title

• G01N23/095

  Gamma-ray resonance absorption, e.g. using the Mössbauer effect · CPC title

• A61B6/541

  involving acquisition triggered by a physiological signal · CPC title